1. Field of the Invention
The invention relates to a process for the search for samples in images of a data base. Interest is here attached to the automatic search for a particular detail within a collection of images recorded in a data base.
2. Description of the Related Art
A simple solution consists of describing the images by a text or by keywords and checking the catalogue resulting from this description. The disadvantage of this very simple method is that it requires time for creating the catalogue and it is not possible to describe the images with sufficient precision or objectivity, particularly as the object of the search is not always known at this time and important elements of images would be neglected. Moreover, an element such as a building, vehicle, person, etc. will generally be described by the category of which it forms part and will consequently only be identified following a visual examination of the image in order to establish whether it does correspond to the sample. Thus, this method is not very practical for numerous data.
Another solution consists of seeking an object by describing its contour or texture and investigating it in the image data bank. For this purpose it is necessary to have digitally analyzed the images in order to extract the corresponding informations therefrom. Unfortunately there is no method for the extraction of a contour or texture of objects which is effective in all cases and such methods fail when the objects are partly masked or in the shade, or when they are differently illuminated on the sample and on one of the images
Another possible method consists of comparing the sample with different parts of the images. The comparison is positive when the points of an image fragment have the same shade as the sample points. However, the calculation times are very long due to the number of comparisons which have to be made and the method also becomes inoperative if the sample is present with a different size or orientation on the images.